Full Freeview on the Hemel Hempstead (Hertfordshire, England) transmitter
 | Google map |  | Bing map |  | Google Earth |  | 51.729,-0.426 or 51°43'43"N 0°25'34"W |  | HP3 8SA |
The symbol shows the location of the Hemel Hempstead (Hertfordshire, England) transmitter which serves 74,000 homes. The bright green areas shown where the signal from this transmitter is strong, dark green areas are poorer signals. Those parts shown in yellow may have interference on the same frequency from other masts.
Are there any planned engineering works or unexpected transmitter faults on the Hemel Hempstead (Hertfordshire, England) mast?
HEMEL HEMPSTEAD transmitter - DAB: Slightly reduced power due to essential engineering from 30 May 10:00 until 30 May 15:56. . 
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Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
The Hemel Hempstead (Hertfordshire, England) mast is not one of the extended Freeview HD (COM7 and COM8) transmitters, it does not provide these high definition (HD) channels: .
If you want to watch these HD channels, either use Freesat HD, or move your TV aerial must point to one of the 30 Full Freeview HD transmitters. For more information see the want to know which transmitters will carry extra Freeview HD? page.
Which Freeview channels does the Hemel Hempstead transmitter broadcast?
If you have any kind of Freeview fault, follow this Freeview reset procedure first.Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Are you trying to watch these 0 Freeview HD channels?
The Hemel Hempstead (Hertfordshire, England) mast is not one of the extended Freeview HD (COM7 and COM8) transmitters, it does not provide these high definition (HD) channels: .
If you want to watch these HD channels, either use Freesat HD, or move your TV aerial must point to one of the 30 Full Freeview HD transmitters. For more information see the want to know which transmitters will carry extra Freeview HD? page.
Which BBC and ITV regional news can I watch from the Hemel Hempstead transmitter?
BBC London 4.9m homes 18.4%
from London W1A 1AA, 30km southeast (138°)
to BBC London region - 55 masts.
ITV London News 4.9m homes 18.4%
from London WC1X 8XZ, 31km southeast (135°)
to ITV London region - 55 masts.
How will the Hemel Hempstead (Hertfordshire, England) transmission frequencies change over time?
| 1984-97 | 1997-98 | 1998-2012 | 2012-13 | 18 Apr 2018 | |||||
| B E T | B E T | B E T | E T | K T | |||||
| C29 | ArqB | ||||||||
| C31 | ArqA | ||||||||
| C34 | _local | ||||||||
| C37 | SDN | ||||||||
| C40 | BBCA | ||||||||
| C41 | ITVwaves | ITVwaves | ITVwaves | D3+4 | |||||
| C42 | _local | ||||||||
| C43 | D3+4 | ||||||||
| C44 | BBC2waves | BBC2waves | BBC2waves | BBCA | |||||
| C46 | BBCB | ||||||||
| C47 | C4waves | C4waves | C4waves | BBCB | |||||
| C50tv_off | SDN | ||||||||
| C51tv_off | BBC1waves | BBC1waves | BBC1waves | ||||||
| C55tv_off | ArqB | ||||||||
| C59tv_off | ArqA |
tv_off Being removed from Freeview (for 5G use) after November 2020 / June 2022 - more
Table shows multiplexes names see this article;
green background for transmission frequencies
Notes: + and - denote 166kHz offset; aerial group are shown as A B C/D E K W T
waves denotes analogue; digital switchover was 4 Apr 12 and 18 Apr 12.
How do the old analogue and currrent digital signal levels compare?
| Analogue 1-4 | 10kW | |
| SDN, ARQA, ARQB, BBCA, D3+4, BBCB | (-7dB) 2kW | |
| Mux 1*, Mux 2*, Mux A*, Mux B* | (-14dB) 400W | |
| Mux C*, Mux D* | (-17dB) 200W |
Local transmitter maps
Hemel Hempstead Freeview Hemel Hempstead DAB Crystal Palace TV region BBC London LondonWhich companies have run the Channel 3 services in the Crystal Palace transmitter area
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Friday, 20 April 2012
HEMEL HEMPSTEAD transmitter - Freeview BBC Digital TV Off Air; DSO related from 00:22 on 18 Apr to 01:05 on 18 Apr [BBC]
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Wednesday, 9 May 2012
A
Andrew Healy2:34 PM
Ashford
James,
in Ashford, I am gforced to use the HH transm itter as my aerial is fixed verticvally (Crystal Palace needs a horizontal one). My reception from HH is OK, but, the ArqivaB multiplex is unreachable- not essential but an annoying glitch. Is there a plan to ramp up the actual power this multiplex ?
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James: Have you replaced your Group B aerial with either a Group E one or a wideband one?
COM5 and COM6 are on the highest channels which are therefore the furthest away from Group B.
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Andrew Healy: I suspect that your problem is different to James's.
You would appear to be outside of HH's main area. Also, Digital UK Tradeview suggests that Midhurst's C55 BBC A mux could be the cause of your trouble. This is co-channel with HH's ArqB.
HH's two other Commercial multiplexes, 50 and 59, are co-channel with two of Midhurst's COMs, but these are at half transmission power with respect to its PSBs (including BBC A on C55).
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Tuesday, 12 June 2012
A
Alain10:40 AM
Berkhamsted
Hi, I am in Berkhamsted, receiving from HH. Before switchover the signal was not brilliant. Now, BBCA and D3+4 are good and very stable but I cannot get SDN, ArqA nor ArqB. Can someone explain this? On the power graph above it seems each mux is transmitted at the same power, so I should receive them as well as the others, no?
Everyone around me seems to be getting their signal from HH (vertically positioned aerial), but is it possible we could get a better signal from CP?.
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Alain: Can you manually tune to these three channels 50, 59, 55, and does your receiver give any indication of signal strength and quality when you do so? Different receivers are designed differently and some give more clues away than others so you might like to try different devices.
The only thing I can wonder is if you are picking up too much signal from another transmitter that uses these three channels, such as Midhurst because your aerial happens to be in a good spot for it.
As well as performing the above test, try a manual tune to C61 and C62 which are also used by Midhurst. See if these give any signal reading.
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A
Alain7:13 PM
Berkhamsted
Dave L: Thanks for you comment. I'll try a manual tune and let you know what I get. However, I'm not sure if it will be possible as it's a tuner card in my PC and I don't have the manual anymore. I'll give it a try anyway.
Is Midhurst not horizontally polarised though? Is it possible to pick anything up with a vertical aerial?
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Alain: To a lesser degree you vertical aerial will pick up horizontally polarised signals.
I have to say that when I made my posting, I was probably clutching at straws with regards a possible explanation.
A terrain plot shows that you are 50 miles from Midhurst with a few hills in the way, so it is probably unlikely to be the cause:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
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Wednesday, 13 June 2012
A
Alain8:21 AM
Berkhamsted
Dave L: Nice graph from Megalithia! Indeed there seem to be obstacle in the way. Could the interferences come from Crystal Palace?
I've done some tests and it is puzzling: I don't get any signal above C44, which is at 100% (whatever that means). Since my card is not HD, I thought I maybe had some quirk in my wiring making it a low pass system cutting off above 700MHz. However, if I manually check C50, C55 and C59, I indeed get a signal strength of 0% but the software indicates that the signal is somehow "locked". I'll have to try and find a manual for my card online and see what this means.
Would you have any idea in the meantime?
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Alain: Crystal Palace can't interfere with Hemel Hempstead because they are on different channels.
I have no idea what your problem might be. It might be worth searching the internet to see if others are in the same position.
There may be a firmware update for the device or there may be new drivers for it that will cure the problem.
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